johnnydeep wrote: ↑Wed Aug 10, 2022 8:27 pm
Ann wrote: ↑Wed Aug 10, 2022 10:12 am
The brightness of the star and the faintness of the nebula in the RGB image reminds me of what happened way back when, when the Hubble Space Telescope was brand new and not fully calibrated (I think), and some astronomers wanted to test Hubble by having it photograph a nebula in the Large Magellanic Cloud. (No, I can't believe it was the Tarantula Nebula.)
What do you mean by that parenthetical remark?
I mean that the Tarantula Nebula is so
bright that you can't miss it, even without processing.
Let's compare with the nebulosities in Orion:
As you can see, there are several nebulosities here. There is the Orion Nebula, of course, and the Running Man Nebula just above it, but there is also Barnard's Loop, and there is the large round Lambda Orionis nebula at top, and there is the red background to the Horsehead Nebula (even though the Horsehead itself is just barely visible as a tiny dark shape). You can see the small but semi-bright slightly yellowish Flame Nebula to the upper left of Alnitak, one of the Belt stars. And you can even faintly make out the Witch Head Nebula at lower right.
Here's my point: There is only one bright nebula here - well, two or possibly three, if you count the Running Man Nebula just above the Orion Nebula and the Flame Nebula to the upper left of Alnitak. In reality not even the Running Man Nebula or the Flame Nebula count: there is one bright nebula in Orion, and that is the Orion Nebula. You can't miss it. But you can
miss all the others.
Let's look at the Large Magellanic Cloud with the help of an extremely cool gif showing SN 1987A blinking on and off:
Cool, eh? It gives you a real sense of what SN 1987 was like. The supernova was so obvious, and yet, for a supernova, it was kind of faint.
But here's the deal. You can see one
obvious nebula in the gif, can't you? And that is the Tarantula Nebula.
You can't miss it. If NASA had tested the HST on the Tarantula Nebula, they couldn't have missed it.